Discoveries

DISCOVERIES

April 22, 2005

ANTARCTIC GLACIERS SHRINK

About 90 percent of the glaciers on the Antarctic Peninsula have shrunk in the past half century, scientists reported today in a study of an area long regarded as a "canary in the coal mine" because of its sensitivity to climate change.

Researchers for the British Antarctic Survey analyzed 100 satellite images and 2,000 aerial photos and found that since 1953, 212 of the 244 glaciers on the west side of the peninsula had retreated an average of about 2,000 feet. Another 32 glaciers in the region grew or advanced by about 1,000 feet in the same period.

"These glaciers do seem to be responding to climate change," said Alison Cook, a cartographer for the British Antarctic Survey. The findings were published today in the journal Science.

The breakup of ice shelves and retreat of glaciers is part of a natural process in the Antarctic that goes back to the end of the last ice age, some 12,000 years ago. The warming could raise sea levels, change ocean currents and alter climatic patterns far away.

Over the past 50 years, the peninsula has warmed about 4 degrees Fahrenheit, more than any other section of the Antarctic. The rest of the continent has warmed by about 2 degrees, researchers say.

Cook and other scientists say the retreat of Antarctica's glaciers may also be a result of increased precipitation and changing regional ocean temperatures. But more research is needed to pin down a cause, they say.

"We don't think there should be any need for major concern about this," Cook said. "But it is one small piece of the overall jigsaw puzzle of what's going on with the earth and its climate."

Cook, who works several months each year from the British Antarctic research station at Rothera, used photos she took with a camera mounted on a twin-engine plane. She compared current photos with others taken by explorers who probed the peninsula as far back as the 1940s.

"These are probably the best photographic records of the Antarctic available," she said.

Cook said she focused on the peninsula because it's the most thoroughly photographed part of the Antarctic. She also limited her research to images and photos of glaciers on the west side of the peninsula because its east side is dominated by the Larsen Ice Shelf - where a 500 billion-ton chunk of ice broke off three years ago.

- Dennis O'Brien

Did you know ...

Crohn's disease is an inflammatory bowel that affects men and women equally and seems to run in some families. Its cause is unknown, but the most popular theory is that the body's immune system reacts to a virus or a bacterium by causing chronic inflammation in the intestine.

- National Digestive Diseases Information Clearinghouse

A spine-tingling exercise machine

Quick Takes

An international chiropractic association has given its seal of approval to a new exercise machine catching the attention of pro athletes for its potential to strengthen spine muscles.

The SpineForce, introduced this year by a French company, looks like a high-tech elliptical trainer. But its motorized, oscillating platform makes your workout like riding a continuous wave. The result: It exercises the deep muscles that support the spine.

Ronald Hendrickson of the International Chiropractors Association calls the technology "exceptionally designed." In fact, the group endorsed SpineForce, making it only the fourth product the association has recommended in 79 years.

Pro athletes are taking notice: Cincinnati Bengals defensive lineman Duane Clemons reportedly bought a $30,000 SpineForce for his own use, according to U.S. distributor LPG One, of Miami. And David Leadbetter also is putting the SpineForce to use at his golf training center in Orlando, Fla.

Bottom line: The technology looks exceptional. But you'll likely have to wait until a gym or doctor buys the SpineForce to get your shot on the machine. - Mary Beth Regan

In Brief

Baltimoreans' mercury levels

Mercury levels in the blood of most older Baltimoreans are not high enough to impair memory or other cognitive functions, according to a recent study.

The implication, said a researcher from the Johns Hopkins Bloomberg School of Public Health, is that recommended federal limits on fish consumption for women and children are probably appropriate for older people, too. Fish is a primary source of mercury, which at even modest levels can damage the nervous system.

"We tried to get a sample that represented average people in Baltimore and see what their [mercury] levels are," said Megan Weil, principal investigator of a study appearing in this week's Journal of the American Medical Association. "Now we know their levels are not too high."